1. Field of the Invention
This invention pertains to internal combustion engines and particularly to such engines where water is injected into the combustion chamber under precisely controlled conditions.
2. Background of the Prior Art
The benefits and gains in fuel economy by the injection of water into the cylinders of an internal combustion engine have long been known. However, all previously known methods of injecting water into the cylinder have inherent drawbacks in design, making mass production of water injected engines undesirable.
Representative of the prior art devices are the following patents: Woolf U.S. Pat. No. 864,877 shows an explosive engine having an inlet duct to the combustion chamber; Meyer U.S. Pat. No. 2,101,554 shows an internal combustion engine having a solenoid operated valve for injecting water into a secondary chamber; Butler U.S. Pat. No. 2,218,522 is an internal combustion chamber having a water injecting valve opening into the combustion chamber; French U.S. Pat. No. 2,489,177 shows a water injection valve in the engine cylinder; Lee U.S. Pat. No. 3,074,228 is a combined internal combustion and steam engine; Eft 4,018,192 discloses a water injection system for internal combustion engines; Thomas U.S. Pat. No. 4,417,441 shows a combustion chamber in the piston head; Van Dal U.S. Pat. No. 4,589,377 has an injector fitted in the combustion chamber; French U.S. Pat. No. 422,950 has a valve injector in the combustion chamber.
In all previous systems, the introduction of water into the combustion chamber was achieved by mechanical means--the injectors are mechanically driven by camshafts, gears or sprockets. In all of the prior known art, any gains made in fuel economy are offset by drawbacks in design. Many previous systems require major mechanical changes in engine design, some are antiquated and have an extensive number of parts prone to failure or breakdown. However, the main disadvantage to all currently known systems of water injection is that control over the injection of the water in response to changing engine requirements is very limited.
Two previously designed systems, (U.S. Pat. Nos. 4,502,420 and 4,558,665) have attempted to solve this problem by controlling the injectors with a computer or electronic control unit. However, these two designs are still mechanical in nature because although the injectors are computer controlled, the actual introduction of water into the cylinder is still limited and ultimately controlled by a mechanically operated valve (the intake valve of the engine). This is highly undesirable because the water can only enter the cylinder when the intake valve is open. Therefore, injection of water can only take place on the intake stroke of the piston.